In recent years considerable attention has been focused upon the development of polymers having high temperature resistance. Such polymers are useful, for instance, in the fabrication of articles including reentry parachutes for space vehicles, and high temperature insulating materials, etc.
BBB type polymers, and particularly poly(bisbenzimidazobenzophenanthroline), are recognized to be useful in the formation of extremely attractive products which are capable of withstanding highly elevated temperatures. These polymers heretofore commonly have been formed in a phosphoric acid medium as reported in commonly assigned U.S. Pat. Nos. 3,539,677 and 3,574,170. Alternatively, these polymers may be formed in a molten Lewis acid solvent as reported in commonly assigned U.S. Ser. Nos. 221,780, filed Jan. 28, 1972 (now abandoned), and 229,178, filed Feb. 24, 1972 (now U.S. Pat. No. 3,798,201). While reference to the possible use of an organic solvent generally has been alluded to in the literature, no organic solvent is believed to have been heretofore proposed which offers the advantages of the present process.
It is an object of the present invention to provide an improved process for the formation of BBB type polymer.
It is an object of the present invention to provide an improved process for the formation of particulate BBB type polymer having an unusually high surface area.
It is an object of the present invention to provide an improved process for the formation of BBB type polymer which may be conducted at a relatively high condensation temperature for a relatively brief reaction time.
It is an object of the present invention to provide an improved process for the formation of BBB type polymer wherein the quantity of polymer formed within a given reaction zone may be substantially greater than that commonly formed employing prior art techniques.
It is another object of the present invention to provide an improved process for the formation of BBB type polymer which may readily be conducted at a highly elevated temperature at atmospheric pressure.
It is another object of the present invention to provide finely divided BBB type polymer having a high surface area which is particularly suited for pressure molding to form three-dimensional shaped articles.
These and other objects, as well as the scope, nature, and utilization of the invention will be apparent from the following description and appended claims.